Plasmatron drive

ABSTRACT

A plasmatron drive wherein the plasmatron is combined with the pneumatic drive rod into an integral unit and the pneumatic drive cylinder is provided with a mechanism for fixing the plasmatron in the upper position.

United States Patent 1 Nautny et al.

[54] PLASMATRON DRIVE [76] Inventors: Konstantin Troiimovich Nautny, ulitsa Krasitskogo, l7, kv. 2; Viktor Iosiiovich Lakomsky, ulitsa Bastionnaya, l0, kv. 30; Anatoly lvanovich Chvertko, bulvar Lesi Ukrainki, 2,

kv. 36, all of Kiev; Semen Yakovlevich Shekhter, ulitsa Brestskaya, l5, kv. l8; AlexandrMikhailovich Reznitsky, ulitsa Kirova, 2,

kv. 18, both of Kommunarsk Voroshilovgradskoi oblasti; Viktor Romanovich Pilipchuk, ulitsa Mashinostroitelnaya, 12, kv. 4, Kiev, all of U.S.S.R.

22 Filed: Nov.9, 1971 21' AppL'No; 197,011

521 u.s.c| ..13/14,1s/|

[ 51 Apr. 3, 1973 I [51] Int. Cl. ..H05b 7/12 [58] Field of Search ..l3/l, 9, 13-17; 219/121 P [56] References Cited UNITED STATES PATENTS 3,524,006 8/1970 Ebeling et al...... ..l3/l X 3,249,673 5/!966 Moore ..l3/l3 UX Primary Examiner-Roy N. Envall, Jr. Attorney-Eric H. Waters et al.

[57] ABSTRACT A plasmatron drive wherein the plasmatron is combined with the pneumatic drive rod into an integral unit and the pneumatic drive cylinder is provided with a mechanism for fixing the plasmatron in the upper position.

2 Claims, 2 Drawing Figures PLASMATRON DRIVE The present invention relates to electrometallurgy and can be used in plasma-arc furnaces for moving the plasmatron.

Widely known in the art is a plasmatron drive of the plasma-arc furnace comprising a pneumatic drive installed on the furnace, said drive having a rod reciprocating vertically inside the cylinder and carrying a rigidily fastened piston connected to the plasmatron.

However, location of the drive in this case side by side with the plasmatron produces bending stresses acting on the rod which reduces its reliability.

Besides, said drive is bulky, inconvenient in operation, takes too long for starting and cannot be used for locating several plasmatrons in the crown of one furnace at close distances from one another which is required by the necessity for adequate heating of the metal bath.

It is an object of the present invention to eliminate the above-mentioned disadvantages. The main object of the present invention resides in providing such a design of the drive, which would ensure the possibility of plasmatron travel towards the metal bath, its return to the upper working position and its locking in this position, as well as the possibility of location of several plasmatrons in the crown of one furnace at close distances from one another.

In accordance with these and other objects, in the plasmatron drive of a plasma-arc furnace comprising a pneumatic drive installed on the furnace chamber, having a rod-shaped plasmatron reciprocating vertically in the cylinder, provided with a rigidly mounted piston, and connected with the plasmatron according to the invention, the rod and plasmatron are combined into an integral unit and the base of the cylinder is provided with a hole for introducing the end of the plasmatron into the furnace chamber, the piston being secured on said plasmatron with a provision for being adjusted along the rod axis and the cylinder has a mechanism for locking the plasmatron in the upper position. Such a design of the drive simplifies the construction considerably and allows several plasmatrons to be closelyspaced in the furnace crown.

Besides, with the gas pressure in the furnace chamber being lower than atmospheric pressure, said mechanism prevents the plasmatron from lowering into the furnace chamber under the action of atmospheric pressure.

The mechanism for locking the plasmatron in the upper position comprises an arrester limiting the travel of said plasmatron, secured on the cylinder and consisting of gripping jaws which are compressed by springs, and stops with tapered surfaces, secured on the plasmatron, said stops entering said jaws when the plasmatron moves upward. 1

Now the invention will be described in detail by way of example with reference to the accompanying drawings, inwhich:

FIG. 1 is a longitudinal section of the drive according to the invention;

FIG. 2 is a section taken along line II-II in FIG] The plasmatron drive is mounted on the crown of the plasma-arc furnace and consists of a pneumatic drive cylinder 1 (FIG.1) with a removable cover 2 and with pipe unions 3 on the lower and upper external surfaces.

The cover 2 and bottom 4 of the cylinder 1 have two coaxial holes for the passage of the rod 5 whose body is combined with the body of the plasmatron 5.

Secured on the external surface of the plasmatron 5 inside the cylinder 1 is a piston 6. The piston 6 is fastened to the plasmatron 5 by means of a collet 7 which allows the position of the piston 6 to be adjusted along the axis of the plasm atron.

The holes in the cover 2 and bottom 4 of the cylinder 1 for the passage of the plasmatron 5 are sealed by vacuum seals 8.

On the cover 2 of the cylinder 1 are diagonally mounted two posts 9 to which the upward-travel arrester 11 of the plasmatron 5 is secured by bolts 10.

Fastened movably inside each pair of the jaws 12, on one of them, is a rod 13 (F102) which extends outside through a hole in the other jaw; the outer end of the rod 13 carries a spring 14 pressed upon by nuts 15 via a sleeve 16 and compressing the jaws 12.

The lower ends of the jaws compressed by the springs 14 form a space with a tapered surface.

Fastened rigidly between the cover 2 of the cylinder 1 and the arrester 11 on the outer surface of the plasmatron 5 is a clamp 17 with stops 18 having tapered surfaces; during the upward travel of said plasmatron 5 said tapered surfaces of the stops 18 are inserted into the space between the jaws 12.

The clamp 17 has two holes receiving two posts 9 a which function as guides for the travel of the plasmatron 5.

The drive operates as follows.

In the initial position before starting, the rodplasmatron 5 occupies the uppermost position in the cylinder 1. The plasmatron 5 is held in this position by the jaws 12 of the grips which receive the tapered surfaces of the stops 18. The force with which the jaws 12 are compressed by the springs 14 is adjusted by nuts 15. The upper position of the plasmatron 5 is adjustable. To limit the upward travel of the plasmatron 5, the arrester 11 with the grips mounted on it is moved along the posts 9 through the required distance from the cover 2 of the cylinder 1 and secured by bolts 10. The stops 18 are fastened on the body of the plasmatron 5 with the aid of the clamp 17 in close proximity to the cover 2 of the cylinder 1 with the plasmatron lowered all the way down.

To excite a plasma-arc between the plasmatron 5 and the metal bath, the air is fed into the upper pipe union 3 of the cylinder 1. The stops 18 force off the jaws 12 and move down together with the plasmatron 5 until the piston 7 secured rigidly on the plasmatron body comes in contact with the bottom of the cylinder 1. After the plasmatron 5 has been excited, the air is fed into the lower pipe union 3 of the cylinder 1, returning the plasmatron to the upper working position in which case the tapered surfaces of the stops 18 again enter the jaws 12 of the grips, holding the plasmatron in this position.

Thus, the use of this drive ensures the travel in it of the plasmatron towards the metal bath (for starting), its returning to the upper working position and its locking in this position. Besides, such an arrangement allows the plasma-trons to be closely spaced which reduces the dimensions of the chamber and improves the thermal effect.

What we claim is:

1. A plasmatron drive for a plasma-arc furnace, comprising a pneumatic drive cylinder arranged on the furnace vault; a plasmatron located within said drive cylinder and extending through holes formed in the a bottom and cover portions thereof, and having a reciprocating motion inside said cylinder, the lower end of said plasmatron passing through the hole in the bottom of said pneumatic drive cylinder extending into the chamber of the furnace; a piston being secured on said plasmatron. within said drive cylinder of the pneumatic drive, saidcylinder being adjustable along the axis of said plasmatron; and a mechanism for locking said plasmatron in the upper position being positioned on top of said pneumatic drive cylinder.

2. A drive as claimed in claim 1, said locking adapted to travel along said plasmatron and beinglocated between said arrester and the upper cover of said pneumatic drive cylinder, said stops entering said jaws during the upward travel of the plasmatron so as to lock the latter into the upper position. 

1. A plasmatron drive for a plasma-arc furnace, comprising a pneumatic drive cylinder arranged on the furnace vault; a plasmatron located within said drive cylinder and extending through holes formed in the bottom and cover portions thereof, and having a reciprocating motion inside said cylinder, the lower end of said plasmatron passing through the hole in the bottom of said pneumatic drive cylinder extending into the chamber of the furnace; a piston being secuRed on said plasmatron within said drive cylinder of the pneumatic drive, said cylinder being adjustable along the axis of said plasmatron; and a mechanism for locking said plasmatron in the upper position being positioned on top of said pneumatic drive cylinder.
 2. A drive as claimed in claim 1, said locking mechanism comprising two posts rigidly fastened to the cover of said pneumatic drive cylinder; an arrester for limiting the travel of said plasmatron being secured to said posts at a height corresponding to the working position of said plasmatron, said arrester including two pairs of gripping jaws compressed by springs; stops having tapered surfaces being rigidly supported on a clamp adapted to travel along said plasmatron and being located between said arrester and the upper cover of said pneumatic drive cylinder, said stops entering said jaws during the upward travel of the plasmatron so as to lock the latter into the upper position. 